Counterweighted take-up system



Sept. 14, 1965 A. R. PHILIPS 3,206,010

COUNTERWEIGHTED TAKE-UP SYSTEM Filed Dec. 15, 1963 JNVENTOR ALBERT R. PHILIPS ATTORNEYS l lI United States Patent O 3,206,010 COUNTERWEIGHTED TAKE-UP SYSTEM Albert R. Philips, Brooklyn, Ghio, assignor to Young Brothers Company, Cleveland, Ohio, a corporation of Michigan Filed Dec. 13, 1963, Ser. No. 330,317 14 Claims. (Cl. 198-20S) The present invention relates generally, as indicated, to a counterweighted take-up system, and, more particularly, to a take-up system for maintaining the tension in the chains of a two-chain conveyor and the like.

Chain conveyors of the type that travel through elongated ovens and either support belts, wickets, or the like adapted to carry objects therethrough or directly supported and convey such objects, are subjected to a wide range of temperatures which causes the links of the conveyor chains to expand and contract, thus resulting in an overall increase and decrease in the length of the chains.

To compensate for such increased and decreased length and to maintain a uniform tension in the conveyor chains, various types of expansion take-up devices have been employed. However, such take-up systems have not been entirely satisfactory since they are too complex and eX- pensive. Further, conventional rack and pinion equalizing systems are subject to a tooth climbing, jerky or nonuniform action.

It is therefore a principal object of this invention to provide a simple expansion take-up system which automatically operates in a smooth, uniform manner to maintain a uniform tension in the chains of an oven conveyor.

It is another object to provide an expansion take-up system including a take-up shaft which can be readily adjustably aligned with the drive shaft of the chain conveyor.

A further object is the provision of a simplified weight operated take-up system utilizing a chain type squaring mechanism for the take-up shaft.

Other objects and advantages of the present invention will become apparent as the following description proceeds.

To the accomplishment of the foregoing and related ends, the invention, then, comprises the features hereinafter fully described and particularly pointed out in the claims, the following description and the annexed drawing setting forth in detail a certain illustrative embodiment of the invention, this being indicative however, of but one of the various ways in which the principle of the invention may be employed.

ln said annexed drawing:

FIG. 1 is a side elevation of a preferred embodiment of an improved expansion take-up system in accordance with the present invention employed on the end of an industrial oven conveyor;

FIG. 2 is a top plan of such expansion take-up system; and

FIG. 3 is a Vertical sectional view taken on the plane of the line 3-3 of FIG. 1.

Referring now more particularly to FIGS. 1 and 2 of the drawing, there is illustrated a counterweighted takeup system 1 mounted on the end support frame 2 of an industrial oven conveyor 3. The support frame 2 includes two sets of laterally spaced upstanding legs 4, 5, and 6 having vertically disposed support plates 7 and 8 secured thereto. Extending between the support plates 7 and 8 are two laterally spaced horizontal support tubes 9 and 10 which are adapted to maintain such support plates in parallel alignment.

Projecting outwardly from the support plate 7 are two horizontally extending platforms 11 and 12 on which aaai Patented Sept. 14, 1965 are mounted a worm gear reducer 13 and a variable speed motor drive unit 14, respectively, such variable speed motor 14 being operatively connected to the gear reducer 13 to drive the same by means of a conventional over running cam clutch arrangement 15 consisting of a cam assembly and a coupling.

Driven by the gear reducer 13 is a drive shaft 16 extending through support plate 7 and journaled in support plate 8. Mounted on the drive shaft 16 for rotational movement therewith are two chain sprockets 17 and 18 having conveyor chains 19 and 20 in engagement therewith.

The automatic expansion take-up system 1 includes a take-up shaft 23, the ends of which project through aligned horizontally extending slots 24 in the support plates 7 and 8 above and to the right of the axis of the drive shaft 16 as viewed in FIG. 1. As can be more clearly seen in FIG. 3, two horizontally disposed guide rails 25 and 26 are secured to the outer surface of each support plate 7 and 8 adjacent the upper and lower surfaces of the slots 24 by means of a plurality of fasteners 27 and 28, such guide rails being adapted to guide unground radial ball bearings 29 mounted adjacent the ends of the take-up shaft 23 during lateral movement of such shaft between the ends of the slots 24.

The ends of the take-up shaft 23 have studs 30 extending axially outwardly therefrom and thrust washers 31 inserted over the studs, such thrust washers being held in place against the shaft ends by means of fasteners 32.

Also mounted on the take-up shaft 23 are two idler sprockets 33 and 34, such idler sprockets being in radial alignment with the conveyor chain drive sprockets 17 and 18, respectively, so that the conveyor chains 19 and 20 in engagement with the drive sprockets 17 and 13 are also in engagement with the idler sprockets 33 and 34. The mounting of the idler sprockets 33 and 34 on the take-up shaft 23 includes ball bearings 35 and 36 which are adapted to allow the idler sprockets to rotate independently or" the take-up shaft rotation and vice versa.

As is readily apparent, when the take-up shaft 23 is adjacent the right end of the slot 24 as viewed in FIG. l, the conveyor chains 19 and 20 will move over a shorter path around the sprockets 17 and 18 than when the takeup shaft is adjacent the left end of such slots. Thus movement of the take-up shaft 23 from the right end of the slots 24 to the left end thereof will take up a considerable amount of slack in the chains 19 and 20. Conversely, movement of the take-up shaft from the left end toward the right end will tend to loosen such chains.

Each end of the take-up shaft 23 is provided with a group of three roller chain sprockets 38, 39, and 40 adjacent the inner surface of the support plates 7 and 8. One sprocket 38 of each group has a chain 41 wrapped therearound in a counterclockwise direction as viewed in FIG. l with one end fastened to the sprocket and the other end hanging downwardly and fastened at 42 to the upper end of a bar 43 having a plate 44 secured to the lower end thereof. Disposed on the plate 44 are two counterweights 45 and 46 having centrally disposed apertures 47 and 48 through which the bar 43 is adapted to extend to maintain such counterweights in their proper position on the plate 44. In the illustrated embodiment, the weight 45 Weighs approximately 50 lbs. and the weight 46 weighs approximately 25 lbs. However, it should be understood that the total weight placed on the plate 44 may be varied, depending on the amount of tension desired on the conveyor chains 19 and 20, as will become readily apparent hereafter.

The force exerted on the chains 41 by the weights 45 and 46 tend to unwrap the chain 41 and thus turn the sprocket 38 of each group and take-up shaft 23 in a counterclockwise direction as viewed in FIG. 1.

The other two sprockets 39 and 40 in each group have similar chains Si) and 51 wrapped in opposite directions therearound, such chains having one end fastened to their respective sprockets and the other end adjustably anchored at 52 and 53 adjacent opposite ends of the take-up shaft travel `defined by the length of the slots 24. The anchors 52 and 53 are formed by releasably securing the chains 50 and 51 to the ends of support tubes 54 and 55 projecting inwardly from the inner surface of the plates 7 and 8, respectively.

As aforesaid, the counterweights 45 and 46 have a tendency to unwrap the chain 41 and turn the sprocket 38 and take-up shaft 23 in a counterclockwise direction as viewed in FIG. 1. As such shaft and sprockets are rotated, the chain 50 of each group is wrapped onto the sprocket 39 while the chain 51 is unwrapped from the sprocket 40. Since the chains 50 and 51 are adjustably anchored at opposite ends of the take-up shaft travel, the take-up shaft 23 must move toward the anchor 52 of the chain 50 being wrapped as it moves away from the anchor 53 of the chain 51 being unwrapped.

Thus the freely rotating idler sprockets 33 and 34 mounted on the take-up shaft 23 are continuously urged to the left as viewed in FIG. 1 to take up any increased length of the conveyor chains 19 and 20 which might occur due to increasing temperatures and to maintain such conveyor chains at a uniform tension through the force of the counterweights 45 and 46 urging the take-up shaft and sprockets 38 to rotate in a counterclockwise direction and cause the take-up shaft to move toward the anchors 52 of the chains 50 as it is wrapped on the sprocket 39.

Should the overall length of the conveyor chains 19 and 20 decrease due to the decreasing temperatures, the idler sprockets 33 and 34 and take-up shaft 23 would be urged toward the right by the force of the chains 19 and 20 acting thereon. During such rightward movement, the take-up shaft would be caused to rotate in a clockwise direction since the chain 50 of each group would have to unwrap from its sprocket 39 to increase its effective length. Moreover, during such rotational movement of the take-up shaft 23 the chain 51 would be wrapped around its sprocket 40, and the chain 41 secured to the bar 43 would be wrapped around the sprocket 38, thus raising the counterweights 45 and 46 and maintaining the conveyor chains 19 and 2th under the same tension as when the overall length of the conveyor chains was increased.

As previously stated, the ends of the chains and 51 are adjustably anchored at 52 and 53. Such a construction provides a simple and convenient method of aligning the take-up shaft 23 with the drive shaft 16-of the oven conveyor 3. By merely adjusting the effective lengths of the chains 50 and 51 of each group, the ends of the take-up shaft 23 can be laterally moved in the slots 24 independently of each other until such take-up shaft is aligned with the drive shaft 16. Such alignment is essential if the take-up shaft 23 is to operate in a smooth and uniform manner.

As shown in FIG. 1, a plunger type limit switch 55 may be disposed on the outer surface of the support plate 7 adjacent the left end of the slot 24 for actuation by the take-up shaft 23 as it approaches the left end of the slot 24. When so actuated, the variable speed motor 14 will automatically stop, thus stopping movement of the conveyor chains 19 and 20. Such automatic halting of the conveyor when the take-up shaft 23 is disposed adjacent the left end of the slots 24 is desirable, since when so disposed, either the conveyor chains 19 and 20 have broken or the chains have expanded to such an extent that the automatic expansion take-up system 1 is no longer effective to maintain the desired tension thereon.

As is readily apparent, should it be desired either to increase or decrease the tension of the conveyor chains 19 and 20, it is only necessary either to increase or decrease the total weight carried by the plate 44.

Other modes of applying the principles of the invention may be employed', change being made as regards the details described, provided the features stated in any of the lfollowing claims or the equivalent of such be employed.

I therefore, particularly point out and distinctly claim as my invention:

1. A counterweighted take-up system for maintaining uniform tension in an endless conveyor which is subject to expansion and contraction, comprising a first shaft having a sprocket mounted thereon about which said endless conveyor passes, a frame for supporting said first shaft and sprocket, a take-up shaft vertically spaced from said first shaft and having an idler sprocket rotatably mounted thereon, means mounting said take-up shaft on said frame for movement to increase or decrease the length of path of said conveyor, counterweight means secured to said take-up shaft for urging the same to rotate in the direction of increasing conveyor path length, and at least two chain means wrapped about said takeup shaft in opposite directions, one end of each of said chain means being secured to said take-up shaft and the other end being adjustably anchored at opposite ends of the path of movement of said take-up shaft, whereby said take-up shaft will move toward the anchor of said chain means being wrapped when said take-up shaft moves away from the anchor of said chain means being unwrapped.

2. In an endless chain conveyor having generally oppositely traveling courses, and end sprocket mounted on a fixed end shaft, an idler sprocket rotatably mounted on a movable shaft the axis of which is parallel to and closely spaced from said fixed shaft, said endless chain passing about said end sprocket and engaging said idler sprocket, means operative to urge said idler sprocket and movable shaft in a direction of increasing conveyor path length, and at least two chain means wrapped about said movable shaft in opposite directions, one end of 'each of said chain means being secured to said movable shaft and the other end being adjustably anchored at opposite ends of the path of movement of said movable shaft, whereby one of said chain means is wrapped and the other is unwrapped during movement of said movable shaft.

, 3. The endless conveyor of claim 2 wherein said chain means are wrapped about idler sprockets rotatablyl mounted on said movable shaft.

4. The chain conveyor of claim 2 wherein said idler shaft extends through horizontally extending slots in a frame for said conveyor, guide rails are secured to said frame adjacent the upper and lower surfaces of said slots, and bearings are mounted on the ends of said idler shaft adjacent said guide rails, whereby said guide rails guide said bearingsand thus said idler shaft during its movement between the ends of said slots.

5. The chain conveyor of claim 2 wherein there are two end sprockets mounted on said fixed end shaft, two idler sprockets rotatably mounted on said movable shaft, and a pair of endless conveyor chains, each of said conveyor chains passing about one of said end sprockets and engaging one of said idler sprockets.

6. The chain conveyor of claim 2 wherein said means operative to urge said idler sprocket and movable shaft in a direction of increasing conveyor path length includes a chain wrapped about a sprocket secured to said movable Shaft, one end of said chain being secured to Said sprocket and `the other end having counterweights secured thereto.

'7. The chain conveyor of claim 4 wherein limit switch means is provided adjacent the end of said slot that defines the maximum limit of increasing conveyor path length operative when engaged by said idler sprocket to stop said conveyor.

8. ln an endless chain conveyor having generally oppositely traveling courses, an end sprocket mounted on an end shaft, a frame for supporting said end shaft, an idler sprocket rotatably mounted on a movable shaft the axis of which is parallel to and closely spaced from said end shaft, said endless chain passing about said end sprocket and engaging said idler sprocket, means mounting said movable shaft on said frame for movement in a direction of increasing or decreasing conveyor path length, means operative to urge said idler sprocket and movable shaft in a direction of increasing conveyor path length, at least one group of two roller chain sprockets secured to said movable shaft, a chain wrapped about each of said chain sprockets, one of said chains being wrapped in one direction and the other of said chains being wrapped in the opposite direction, one end of said chains being fastened to their respective sprockets and the other end being secured to opposite ends of the take-up shaft travel, whereby one of said chains is wrapped and the other is unwrapped during movement of said movable shaft along its path of travel.

9. The endless 4chain conveyor of claim 8 wherein there are two groups of said roller chain sprockets, one group 4being mounted adjacent each end of said movable shaft.

16'. The conveyor of claim 8 wherein said means operative to urge said idler sprocket and movable shaft in a direction of increasing conveyor path length includes a third roller chain sprocket in each group of sprockets and a chain wrapped about said third sprocket, one end of said chain being secured to said sprocket and the other end having weights attached thereto.

11. In combination, an endless chain conveyor and a counterweighted take-up system for maintaining .a uniform tension therein, said endless chain conveyor including a frame member, an end shaft having a sprocket mounted thereon about which an endless chain having generally parallel oppositely traveling courses extends, and means for driving said end shaft and thus said endless chain; said counterweighted take-up system including a take-up shaft vertically spaced from said end shaft and having an idler sprocket rotatably mounted thereon, said endless chain engaging said idler sprocket, means mounting said takeup shaft for movement on said frame in a direction of increasing or decreasing conveyor path length, means operative to urge said idler sprocket and take-up shaft in a direction of increasing conveyor path length, and at least two chain means wrapped about said take-up shaft in opposite directions, one end of each of said chain means being secured to said movable shaft and the other end being adjustably anchored at opposite ends of the path of movement of said take-up shaft, whereby one of said chain means is wrapped and the other is unwrapped during movement of said take-up shaft.

12. The combination of claim 11 wherein said idler shaft extends through horizontally extending slots in said frame member, guide rails are secured to said frame member adjacent the upper and lower surfaces of said slots, and bearings are mounted on the ends of said idler shaft adjacent said guide rails, whereby said guide rails guide said bearings and thus said idler shaft during its movement between the ends of said slots.

i3. The combination of claim 11 wherein there are two end sprockets mounted on said end shaft, two idler sprockets rotatably mounted on said take-up shaft, and a pair of endless conveyor chains, each of said chains passing about one of said end sprockets and engaging one of said idler sprockets.

14. The combination of claim 13 wherein said means operative to urge said idler sprocket and movable shaft in a direction of increasing conveyor path length includes a chain wrapped about a sprocket secured to said movable shaft, one end of said chain being secured to said sprocket and the other end having counterweights secured thereto.

References Cited by the Examiner UNITED STATES PATENTS 3,054,499 9/62 Petix 198-208 SAMUEL F. COLEMAN, Primary Examiner. 

1. A COUNTERWEIGHTED TAKE-UP SYSTEM FOR MAINTAINNG UNIFORM STATION IN AN ENDLESS CONVEYOR WHICH SUBJECT TO EXPANSION AND CONTRACTION, COMPRISING A FIRST SHAFT HAVING A SPROCKET MOUNTED THEREON ABOUT WHICH SAID ENDLESS CONVEYOR PASSES, A FRAME FOR SUPPORTING SAID FIRST SHAFT AND SPROCKET, A TAKE-UP SHAFT VERTICALLY SPACED FROM SAID FIRST SHAFT AND HAVING AN IDLER SPROCKET ROTATABLY MOUNTED THEREON, MEANS MOUNTING SAID TAKE-UP SHAFT O N SAID FRAME FOR MOVEMENT TO INCREASE OR DECRASE THE LENGTH OF PATH OF SAID CONVEYOR, COUNTERWEIGHT MEANS SECURED TO SAID TAKE-UP SHAFT FOR URGING THE SAME TO ROTATE IN THE DIRECTION OF INCREASING CONVEYOR PATH LENGTH, AND AT LEAST TWO CHAIN MEANS WRAPPED ABOUT SAID TAKEUP SHAFT IN OPPOSITE DIRECTIONS, ONE END OF EACH OF SAID CHAIN MEANS BEING SECURED TO SAID TAKE-UP SHAFT AND THE OTHER END BEING ADJUSTABLY ANCHORED AT OPPOSITE END SOF THE PATH OF MOVEMENT OF SAID TAKE-UP SHAFT, WHEREBY SAID TAKE-UP SHAFT WILL MOVE TOWARD THE ANOCHOR OF SAID CHAIN MEANS BEING WRAPPED WHEN SAID TAKE-UP SHAFT MOVES AWAY FROM THE ANCHOR OF SAID CHAIN MEANS BEING UNWRAPPED. 